U.S. patent number 4,474,515 [Application Number 06/349,049] was granted by the patent office on 1984-10-02 for expansion fastener.
This patent grant is currently assigned to The Shur-Lok Corporation. Invention is credited to Kenneth H. Pitzer.
United States Patent |
4,474,515 |
Pitzer |
October 2, 1984 |
Expansion fastener
Abstract
The utility of an expansion fastener including an externally
threaded shaft having a head shaped so as to be capable of being
engaged by a manipulative tool, a generally cylindrical
longitudinally split sleeve located around the shaft, a nut
threaded on the shaft, the sleeve and the nut including coacting
surfaces capable of expanding the sleeve as the nut is moved on the
shaft can be improved by utilizing coacting structures on the end
of the sleeve remote from the head and on the nut for preventing
relative rotation between the sleeve and the nut as the shaft is
turned. Preferably the sleeve is twisted slightly in a spiral-like
manner so that an end of the sleeve serves as one of the coacting
structures which engages an adjacent ridged or other not smooth
surface of the nut serving as the other coacting structure. An edge
or an irregular surface of both at the other end of the sleeve can
effectively be utilized to hold the sleeve against rotation
relative to a panel or similar member as the shaft is turned
relative to the nut.
Inventors: |
Pitzer; Kenneth H. (Los
Angeles, CA) |
Assignee: |
The Shur-Lok Corporation
(Irvine, CA)
|
Family
ID: |
23370700 |
Appl.
No.: |
06/349,049 |
Filed: |
February 16, 1982 |
Current U.S.
Class: |
411/16; 411/51;
411/60.2 |
Current CPC
Class: |
F16B
29/00 (20130101); F16B 13/066 (20130101) |
Current International
Class: |
F16B
13/06 (20060101); F16B 29/00 (20060101); F16B
013/04 () |
Field of
Search: |
;411/16,18,49,50,51,60,61,62,57,44,55,151,152,479 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
1900911 |
|
Nov 1969 |
|
DE |
|
2211713 |
|
Sep 1973 |
|
DE |
|
653970 |
|
Nov 1928 |
|
FR |
|
1028264 |
|
Feb 1953 |
|
FR |
|
743651 |
|
Jan 1956 |
|
GB |
|
1449452 |
|
Sep 1976 |
|
GB |
|
2001148 |
|
Jan 1979 |
|
GB |
|
Primary Examiner: Holko; Thomas J.
Assistant Examiner: Whitcomb; Adrian
Attorney, Agent or Firm: O'Brian; Edward D. Boswell; K.
H.
Claims
I claim:
1. An expansion fastener which is adapted to be supported within a
hole in a first member in such a manner as to extend from said
first member and to be inserted into a hole in a second member and
manipulated so as to be expanded into engagement with the interior
of said hole in said second member, said fastener including,
an externally threaded shaft, a head shaped so as to be capable of
being engaged by a manipulative tool located at one end of said
shaft, a longitudinally generally split--between its ends--,
cylindrical sleeve located around said shaft, a nut threaded on
said shaft, said nut and said sleeve being separate, unattached
parts, said sleeve and said nut including coacting expansion
surfaces serving to expand said sleeve as said nut is moved on said
shaft towards said head in which the improvement comprises:
said sleeve is formed of a material capable of serving as a spring
and is twisted between its ends in such a configuration that it is
capable of being compressed between its ends during use of said
expansion fastener,
a holding means comprising an extending edge on the end of sleeve
closest adjacent to said head for preventing rotation of said
sleeve by engagement with said first member when said fastener is
located so that said shaft extends through said hole in said first
member with said head on one side of said first member and said
sleeve on the other side of said first member, said holding means
being located on the end of said sleeve closest adjacent to said
head so as to be capable of being drawn into engagement with said
first member,
coacting rotation preventing means, one of said coacting rotation
preventing means comprising an extending edge located on the end of
said sleeve remote from said head, the other of said coacting
rotation preventing means comprising a surface on said nut located
on said nut adjacent to said sleeve, said coacting rotation
preventing means serving to prevent relative rotation between said
sleeve and said nut when said sleeve and said nut are in contact
with one another.
2. An expansion fastener as claimed in claim 1 wherein:
said expansion surface on said nut is a conically shaped surface on
the side of said nut closest adjacent to said first member,
said conically shaped surface also being said surface serving as
one of said coacting rotation preventing means.
3. An expansion fastener as claimed in claim 2 wherein:
said expansion surface on said sleeve is an internal terminal
portion of said sleeve.
4. An expansion fastener as claimed in claim 1 wherein:
said expansion surface is a conically shaped surface on the side of
said nut closest adjacent to said first member,
said surface serving as one said coacting rotation preventing means
comprising a non-smooth surface extending in a band around said
conically shaped surface.
5. An expansion fastener as claimed in claim 4 wherein:
said expansion surface on said sleeve is an internal terminal
portion of said sleeve.
Description
BACKGROUND OF THE INVENTION
The invention set forth in this specification pertains to new and
improved expansion fasteners. More specifically the invention set
forth in this specification pertains to an expansion fastener each
of which is adapted to be supported within a hole in a first member
in such a manner so as to be capable of being inserted into a hole
in a second member and which is adapted to be manipulated when a
part of it is within the hole in the second member so as to be
expanded into engagement with the interior of the hole in the
second member. Expansion fasteners of this category may be utilized
with a wide variety of different applications. They are primarily
utilized in various different locations where that it is only
possible to gain access to the hole in the second member from one
side or surface of the second member.
It is possible to construct expansion fasteners capable of being
utilized in the manner indicated in the preceding paragraph in a
number of different ways. It is considered that it has been most
advantageous to construct expansion fasteners capable of being
utilized as discussed in the preceding in the manner indicated in
the Pitzer U.S. Pat. No. 3,373,648, issued Mar. 19, 1968 entitled
"Fasteners with Expansion Sleeve". Fasteners of the type referred
to in this discussion and in this patent have normally been
constructed so as to utilize an externally threaded shaft provided
with a head capable of being engaged with a manipulative tool so as
to turn the shaft, a generally cylindrical, longitudinally split
sleeve located around the shaft and a nut threaded on the shaft. In
such a structure the sleeve and the nut include coacting conical
surfaces serving to expand the sleeve as the nut is moved on the
shaft towards the head. Because of their functions these surfaces
can be referred to as expansion surfaces.
Fasteners of this type are normally constructed so that the shaft
is capable of fitting through a hole in a first member but so that
neither the head on the shaft nor the sleeve is capable of passing
through this hole. A fastener of the type described herein is
normally assembled on such a first member with the head and the
sleeve on opposites sides of the first member so that both the
sleeve and the nut extend outwardly around the shaft from one side
of the first member. In this type of fastener normally both the nut
and the unexpanded sleeve are dimensioned so as to be capable of
fitting through a hole in a second member as previously indicated.
Further these parts are dimensioned so that only a comparatively
limited amount of rotation of the threaded shaft is necessary in
order to expand the exterior of the sleeve into contact with the
interior of the hole in the second member.
One of the major problems encountered with prior expansion
fasteners of the type discussed in the preceding concerns the fact
that dimensions of the parts with the sleeve in an unexpanded
configuration should be such that there will be no relative
rotation between the sleeve and the hole in the second member. When
such relative rotation occurs the fastener will not expand as it is
used but will rotate freely as the head of the shaft is turned.
This, of course, is undesirable. In order to insure adequate
friction to insure expansion it has been very important to
dimension the parts so that there is a degree of contact between
them sufficient to inhibit such relative rotation. This, of course,
is somewhat expensive and, hence, undesirable.
BRIEF SUMMARY OF THE INVENTION
From the preceding it is believed that it will be apparent that
there is a need for new and improved expansion fasteners of the
type previously identified. The invention is intended to fulfill
this need. The invention is intended to provide fasteners of the
type indicated which are not apt to rotate freely instead of
expanding during normal conditions of its use. A closely related
objective of the invention is to provide fasteners as indicated
which are constructed in such a manner that rotation of the
threaded shaft in the fastener will always result in expansion of
the fastener under normal conditions of use. The invention is
further intended to provide expansion fasteners as noted which can
be conveniently and easily manufactured at a comparatively nominal
cost and which are capable of giving prolonged, reliable,
satisfactory service.
The various objectives of this invention are achieved by providing:
An expansion fastener which is adapted to be supported within a
hole in a first member in such a manner as to extend from said
first member and to be inserted into a hole in a second member and
manipulated so as to be expanded into engagement with the interior
of said hole in said second member, said fastener including, an
externally threaded shaft, a head shaped so as to be capable of
being engaged by a manipulative tool located at one end of said
shaft, a longitudinally generally split, cylindrical sleeve located
around said shaft, a nut threaded on said shaft, said sleeve and
said nut including coacting expansion surfaces serving to expand
said sleeve as said nut is moved on said shaft towards said head in
which the improvement comprises: a holding means for preventing
rotation of said sleeve by engagement with said first member when
said fastener is located so that said shaft extends through said
hole in said first member with said head on one side of said first
member and said sleeve on the other side of said first member, said
holding means being located on the end of said sleeve closest
adjacent to said head so as to be capable of being drawn into
engagement with said first member, coacting rotation preventing
means, one of said coacting rotation preventing means being located
on the end of said sleeve remote from said head, the other of said
coacting rotation preventing means being located on said nut
adjacent to said sleeve, said coacting rotation preventing means
serving to prevent relative rotation between said sleeve and said
nut when said sleeve and said nut are in contact with one
another.
BRIEF DESCRIPTION OF THE DRAWINGS
Because of the nature of this invention it is best more fully
described in reference to the accompanying drawing in which:
FIG. 1 shows an expansion fastener of the present invention in side
elevation as this fastener is supported within a hole in a first
member such as a panel and as the fastener is located adjacent to a
hole in a second member such as a panel, these two members being
shown in cross section in this view; and
FIG. 2 is a view corresponding to FIG. 1 in which the fastener is
located within the hole in the second member and is used to secure
the two members next to one another, the fastener being partially
in section in this view.
The particular expansion fastener shown in the drawing is a
presently preferred embodiment or form of a fastener in accordance
with this invention. Those skilled in the art of the design and
construction of various types of fasteners will be able to design
other somewhat differently appearing fasteners utilizing the
principles or concepts of this invention defined in the appeneded
claims through the use or exercise of routine engineering skill.
For this reason the invention is not to be construed as being
limited to expansion fasteners which are constructed exactly in the
manner illustrated in the drawing.
DETAILED DESCRIPTION
In the drawing there is shown an expansion fastener 10 in
accordance with this invention in which all of the parts are formed
of a metal such as steel. This fastener 10 includes an externally
threaded shaft 12 carrying an enlarged conventional head 14 which
is adapted to be engaged by a manipulative tool such as, for
example, a screw driver (not shown) when this shaft 12 is to be
turned. If desired the shaft 12 and the head 14 may be referred to
as a machine screw. It is considered preferable, however, to
utilize the terminology employed in the preceding because it is
conceivable that the fastener 10 of the present invention may be
formed sufficiently large so as to not have the appearance of a
conventional machine screw.
This fastener 10 includes a nut 16 having an internally threaded
hole 18 which is threaded upon the shaft 12. This nut 16 is
provided with a generally conical expansion surface 20 located
symmetrically around the hole 18. When the nut 16 is located on the
shaft 12 this expansion surface 20 increases in dimension according
with the distance away from the head 14. If desired the nut 16 can
have a somewhat domelike end 22 adjacent to the expansion surface
20 which will serve to reinforce the periphery 24 of the nut 16
against deformation as the fastener 10 is used.
The fastener 10 also includes a sleeve 26 of a generally
cylindrical shape. This sleeve includes a longitudinally extending
slot or slit 28. Preferably the sleeve 26 differs from a
cylindrical shape slightly in that it is deformed or twisted
substantially as illustrated in FIG. 1 of the drawing. If desired
this particular configuration may be referred to as a partially
spiral or helical configuration. As a result of being twisted as
shown the sleeve 26 may be regarded as a type of elongated coil
spring which includes two end edge portions 30 and 32 which extend
generally outwardly away from one another on opposites of the slit
28 as illustrated in FIG. 1. Preferably the internal diameter of
the sleeve 26 is sufficient that it will fit relatively loosely
around the shaft 14. The internal diameter of this sleeve 26
should, however, be sufficiently small so that the sleeve 26 will
fit generally against the surface 20 adjacent to the hole 18. This
will permit expansion of the sleeve 26 subsequently described.
Prior to the use of the fastener 10 the shaft 12 is inserted
through a hole 34 in a first member or panel 36 so that the head 14
rests against this first member 36. The sleve 36 and the nut 14 are
then assembled on the shaft 26 as indicated in FIG. 1. Preferably
the nut 16 is tightened down during such assembly to a sufficient
extent so that the portion 30 frictionally engages the first member
36 and so that the portion 32 frictionally engages the surface 20
approximately as illustrated in FIG. 1. At this point the portion
30 will serve as a holding means which will prevent rotation of the
sleeve 26 relative to the first member 36. The portion 30 will, of
course, continue to serve this function as the sleeve 26 is
thereafter tightened down upon the shaft 12.
Also the portion 32 on the sleeve 26 will engage the surface 20 and
tend to "bite" into this surface to a sufficient extent to prevent
relative rotation between the sleeve 26 and the nut 16 as this nut
16 is tightened down upon the shaft 12. Because of this the portion
32 can be referred to as a "rotation preventing means" which coacts
with the surface 20 as this surface serves as another "rotation
preventing means". In the event that the nut 16 is formed of a
sufficient hard material that the portion 32 will not bite into the
nut 16 so as to block such relative rotation it is desirable to
utilize a nonsmooth surface 38 on the surface 20 as a rotation
preventing means which cooperates with the portion 32. This surface
38 extends in a band around the surface 20 which is transverse to
the axis of the hole 18. Preferably it consists of a series of
logitudinal extending ridges 40 located immediately adjacent to one
another as shown.
In the event that either the sleeve 26 or the first member 36 are
of such relative hardness that the portion 30 will not adequately
"bite" into and hold the first member 36 it is possible to locate a
nonsmooth surface 42 such as a knurled surface on the sleeve 26
adjacent to the portion 30 so as to increase the relative friction
between the sleeve 26 and the member 36. A similar surface 44 can
be located on the sleeve 26 adjacent to the portion 32 for engaging
the surface 20 for the same purpose.
After the fastener 10 has been assembled as described it can be
used by inserting through a hole 46 in a second member 48 as
indicated in FIGS. 1 and 2 of the drawings. This hole 46 should be
sufficiently large so as to pass around the periphery 24 of the nut
16 and the exterior 50 of the sleeve 26. Also this hole 46 should
be of a dimension reasonably corresponding to slightly less than
the maximum amount that the sleeve 26 can be expanded as
subsequently described as the fastener 10 is used. Such use of the
fastener 10 is rather simple.
After the second member 48 has been located generally around the
sleeve 26 such use involves applying a manipulative tool (not
shown) to the head 14 so as to rotate the shaft 12. As this occurs
the nut 16 will draw down on the shaft 12 generally towards the
sleeve 26. This will cause the portion 30 to firmly engage the
first member 36 so as to secure the sleeve 26 against rotation and
will cause the portion 32 to also engage the surface 20 and the
ridge 40 so as to firmly secure the nut 16 against relative
rotation with respect to the sleeve 26.
Concurrently an internal terminal edge 52 on the sleeve 26 will
move against the surface 20 so as to coact with this surface 20 in
order to expand the sleeve 26. The edge 52 is preferably slightly
rounded to prevent any possibility of it biting into the surface
20. If desired this edge 52 can be replaced with a beveled surface
(not shown). Because of its function this edge 52 may be referred
to as an expansion surface which coacts with the surface 20. As the
sleeve 26 expands it, of course, will be compressed so as to be
placed under compression while concurrently it will be expanded
outwardly. Such outward expansion will increase its effective
diameter to a sufficient point that the interior of the hole 46
will be firmly engaged so as to secure the second member 48 in a
location as shown in FIG. 2 of the drawings.
* * * * *